A slip ring assembly is typically provided on the rotatable rotor shaft of an autombobile alternator or like electrical generating apparatus for effecting electrical contact between the rotor of the apparatus and the associated, relatively fixed electrical contact brushes. Such an assembly typically includes an electrically non-conductive body which carries a pair of axially spaced, annular members referred to as slip rings. A pair of terminals are provided which are respectively electrically joined to the slip rings, with the terminals typically extending axially together from one end of the assembly for connection to the windings of the rotor assembly. The slip rings are typically positioned for respective electrical contact with a pair of the relatively fixed, non-rotating contact brushes to provide the desired electrical connection between the brushes and rotor assembly.
In the past, slip ring assemblies of the above type have typically been manufactured by a compression molding process. Specifically, each of the annular slip rings of the assembly is formed and joined to a respective one of the pair of terminals. Each slip ring and its terminal are then positioned within a mold cavity, with the slip rings positioned in the desired axially spaced relation. A charge of electrically non-conductive moldable material is then introduced into the mold cavity, and the mold cavity is closed and the material compressed to form the body of the slip ring assembly within and about the slip rings and terminals. The body portion of the assembly is typically formed with an axial bore to facilitate mounting of the assembly on an associated rotor shaft, with the body portion acting to electrically insulate the slip rings from each other while maintaining them in the desired axially spaced relation.
In order to assure long and reliable service life, it is desirable that slip ring assemblies be manufactured to exhibit relatively small manufacturing tolerances. In this regard, however, the above compression molding technique has been found to be somewhat disadvantageous in providing highly consistent and accurate molding.
It is therefore desirable to provide a slip ring assembly which facilitates efficient and consistent manufacture, thus desirably enhancing the overall efficiency of the manufacturing process. The slip ring assembly of the present invention has been particularly configured with the goals of efficient and consistent manufacture, with a method of making the present slip ring assembly disclosed herein which can be efficiently performed by taking advantage of well-developed injection-molding techniques.